It is desirable to perform a study of the elastic responses of submarine hulls and internally attached structures to underwater shock loading. In view of the expense and possible involvement of non-shock testable equipment it is not always desirable to perform actual shock tests utilizing real hulls or SSTV's (Submerged Shock Test Vehicles). With the advent of large scale computing power, numerical methods now exist to predict equipment/hull responses. The ELSHOK (ELASTIC SHOCK) computer code is used to perform a parametric study on a submerged shell with an internally attached substructure. Of particular interest is the phenomenon of dynamic amplification or lack of such in the response of this particular substructure and effects on substructure shell interaction due to varying substructure mass and stiffness subjected to underwater explosion side-on shock loading.